U.S. health officials Friday announced a recall of some Boar's Head liverwurst and other deli meats as they investigate a listeria outbreak that has sickened nearly three dozen people and caused two deaths.

Boar's Head Provisions Co. recalled its liverwurst because it may be tainted with the listeria bacteria, the U.S. Agriculture Department said. The company is also recalling additional deli meats that were produced on the same line and on the same day as the liverwurst.

The USDA said a sample of Boar's Head liverwurst from a Maryland store tested positive for listeria. The sample was from an unopened package, collected by the Maryland Department of Health as part of an investigation into the listeria outbreak.

Testing is underway to determine if the liverwurst sample is connected to the outbreak, health officials said.

The outbreak was first reported last week. As of Thursday, 34 people were sickened, with all but one hospitalized. Two people died.

People most commonly reported eating deli-sliced turkey, liverwurst and ham, officials said.

Listeria can contaminate food and sicken people who eat it. Symptoms include fever, muscle aches, nausea and diarrhea. It can be treated with antibiotics, but it is especially dangerous to pregnant women, newborns, the elderly and those with compromised immune systems.

An estimated 1,600 people get listeria food poisoning each year and about 260 die, according to the Centers for Disease Control and Prevention.

The Boar's Head recall includes a number of products stamped with an August 10 sell-by date, including bologna, garlic bologna, beef bologna, beef salami, Italian Cappy-style ham and Extra Hot Italian Cappy-style ham. Also included is Steakhouse Roasted Bacon Heat and Eat, with a sell-by date of Aug. 15.